Now, another challenge arised: for my another project I need to power esp32 from single cell li-ion battery, and also to provide clean supply to sensors to not distrub measurements.
i thought that i will do boost+ldo but the problem is that esp32 needs 500mA on its power rail, so i will loose consoderable power in such configuration. instead i decided to go for buck-boost directly from li-ion to 3v3@500mA with something like tps53000.
For sensors+adc I want to use original boost+ldo design as they consume almost nothing. also to make things interesting i want to use charge pump as a boost. i hope that this will help reduce emi on analog 5v, but as i already have dcdc i have some doubts. anyway it worth the try.
i use external adc so this way i will limit amount of digital noise coming to the sensors. now, i'm interesting to which power i should pullup i2c comm between adc and esp32: i2c is open drain so if i tie it to digital 3v3 it noise should not go directly into supply rail. or if i tight it to clean analog then esp32 pins will also not interfere with analog supply, but i dont like cureent loops from digital to analogue parts. dunno.
so I'm going after something like that:
